Alterations in dynamic effective connectivity of brain functional networks in patients with high myopia: a Granger causality analysis

BACKGROUND: Although previous neuroimaging studies have revealed alterations in the static brain networks of patients with high myopia, little is known about changes in their dynamic brain networks, particularly regarding directional connectivity within these networks, warranting further investigation. METHODS: In this study, resting-state functional MRI was conducted on 82 confirmed patients with high myopia and 59 healthy controls. Employing dynamic Granger causality analysis, sliding time windows, and K-means clustering, we assessed dynamic alterations in effective connectivity within the brain's functional networks in patients with high myopia. RESULTS: Patients with high myopia show significantly enhanced dynamic effective connectivity (dEC) between the visual network and the default mode network (DMN) compared with healthy controls. Furthermore, aberrant connectivity is detected between the visual network and the limbic network. In addition, intravisual network dEC is markedly increased. In state 1, the frequency differed significantly between the two groups, with high myopia patients showing a markedly higher frequency than healthy controls. CONCLUSION: This study found that patients with high myopia exhibit significantly altered patterns of dEC, especially increased connectivity between the visual network, the DMN, and the limbic network. Furthermore, significantly increased intranetwork dEC within the visual network indicates enhanced internal visual information processing. These findings offer new insights into the neural mechanisms of high myopia and suggest that long-term visual impairment may trigger functional reorganization in both visual and nonvisual brain networks.